The large interest for pulp production increases the search for new technologies capable to optimize the current production processes. From 2008 to 2009, the world production of pulp increased 4,9% on average, and approximately 90% of that production are originate from kraft process. The kraft process presents great advantages on the other ones, as the adaptation to all types of wood, production of high quality pulps with excellent properties of resistances and an efficient system of recovery of chemical reagents and energy. The relevance of this process provided several modifications. Nowadays, modified process makes use of classified chips with thickness between 2 to 4mm. Besides, the cooking conditions are based on the distribution of alkaline rates with low temperatures and long times of cooking, what implicates in equipments of larger volume. In that way, the present project will analyze the chip thickness inserted in modified cooking. The used wood will be from commercial plantings of Eucalyptus urophylla x Eucalyptus grandis hybrid, with 7 years originating from São Paulo State. For each species will be select 5 trees with medium diameter. The trees will be cut in those heights: base, 25, 50, 75 and 100% of the commercial height (up to 6 cm of diameter). The sections of wood will be dividing in 2 groups that will be process in a cutter to obtain conventional chips and for processing in a generator of particles to obtain chips with thickness of 2.0mm, 1.0mm and 0.5mm. Characterization and modified cooking will be accomplished, besides the bleaching of the pulps. The acquisition of data will allow to determine the impact of the chip thickness in the produced pulp, in order to obtain the guidelines for the establishment of a new pulping process previously denominated of "flash cooking ", as well as to establish the technological bases for optimization of the systems used in industrial scale.
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